At the source of computational hardness for general games is the combinatorial number of mixed strategies that the algorithm has to consider.
In contrast, congestion games admit pure equilibria, which makes them a prime candidate for tractable equilibrium computation.
The seminal work of [1]} (see also [2]}, [3]}) ruled out the most immediate application of this idea: while pure equilibria exist for congestion games, finding them is again intractable.
But more generally, it is natural to hope that the special structure of congestion games allows for efficient computation of (possibly mixed) Nash equilibria.
